The present invention relates in general to a composite wick structure of a heat pipe, and more particularly, to a wick structure fabricated from a woven mesh and a sintered powder.
Having the features of high heat transmission capability, high-speed heat conductance, high thermal conductivity, light weight, mobile-elements free, simple structure, the versatile application, and low power for heat transmission, heat pipes have been popularly applied in heat dissipation devices in the industry. The conventional heat pipe includes a wick structure on an internal sidewall of a tubular member. The wick structure typically includes a woven mesh or sintered powder to aid in transmission of working fluid.
However, the woven mesh or the sintered powder each has advantages and drawbacks.
For example, the fine and dense structure of the sintered-powder wick structure provides better capillary force for reflow of the liquid-state working fluid. However, during fabrication, an axial rod has to be inserted into the tubular member to serve as a support member of the wick structure during the sintering process, so as to avoid collapse of the powdered which has not been sintered yet. Therefore, the thickness of the sintered powder wick structure is thicker. Consequently, the capillary thermal resistance is increased to be disadvantageous to the heat transmission. Further, requirement of the axial rod hinders the mass production of the heat pipe and causes fabrication and quality issues of the heat pipe.
The woven mesh wick structure does not require the axial rod, such that the problems of the sintered powder wick structure do not encounter. Further, the woven mesh wick structure is more easily to fabricate compared to the sintered-powder wick structure. However, as the woven mesh is made by weaving metal wires, the porosities are larger to provide a poor capillary effect. The working fluid is less easily to reflow, and the thermal conduction efficiency is affected.
Thus, there still is a need in the art to address the aforementioned deficiencies and inadequacies.